MetconA or B ... (what you need to work on ... or something different ...)C for those avoiding the run / row ...D for those that can already run a sub 4hr marathon ...***Your Cardiovascular Endurance will NOT get better if you keep avoiding it ...Laps around the Plaza will allow you to work up to a "tolerable" distance- see how far you can make it, you can go further than you realize, just do it ..